A jog wheel is a type of device to allow a user to navigate through audio or video content. As the jog wheel is turned, the media typically shifts in a direction (e.g., fast-forward, reverse, left, right) according to which way the wheel is turned. For example, if the user turns the jog wheel clockwise, then the media typically advances. In contrast, if the user turns the jog wheel counter-clockwise, then the media typically reverses. Jog wheels also have been implemented as scroll wheels on computer mice. More recently, jog wheels also have been implemented as menu selection interfaces on devices such as personal digital assistants and music players. For example, jog wheels may be used to scroll through menu entries and to make menu selections.
The speed at which the media advances or reverses (or the menu selections scroll) typically depends on how the jog wheel is turned. How the user turns, or simulates turning, the jog wheel is a function of the type of jog wheel that is implemented. For multi-spin jog wheels, the jog wheel may be rotated endlessly, so that the speed at which the media advances or reverses usually corresponds to how fast the user rotates the jog wheel. For single-turn jog wheels, the rotational movement of the jog wheel is limited (e.g., typically limited to less than one full rotation) by fixed stops, and the speed at which the media advances or reverses usually corresponds to how far toward one side the user rotates the jog wheel.
A jog wheel also may be referred to as a jog dial, a shuttle dial, or a shuttle wheel. In some instances, the term “jog” is used to refer to slow navigational speeds, while the term “shuttle” is used to refer to fast navigational speeds. However, no distinction between “jog” and “shuttle” is made in the present description.
Conventionally, two technologies have been used to implement jog wheels. Specifically, conventional jog wheels are typically implemented using either capacitive sensing or magnetic sensing. In one conventional implementation of capacitive sensing, the jog wheel has a capacitive circuit such as one or more layers of conductive traces built into it to detect a change in capacitance due to the movement of a nearby conductive object such as a user's finger. In some instances, the capacitive jog wheel does not actually rotate, but the capacitive circuitry senses the simulated rotation by a finger, stylus, or other conductive object.
In magnetic sensing implementations, the jog wheel may be implemented with a hall effect sensor. A hall effect sensor is a transducer that generates a voltage in response to a change in the magnetic field density. Typically, the hall-effect sensor detects a magnetic field from a passing current-carrying conductor (or, alternatively, detects a changing current in a fixed conductor). By arranging the current-carrying conductor and the sensor in relative positions on and off the jog wheel, the hall effect sensor can detect the rotation of the jog wheel. If multiple hall effect sensors are used, the circuitry may be able to indicate partial rotation of the jog wheel and the rotational direction of the jog wheel.
The use of these conventional technologies may result in relatively thick jog wheels. In other words, the size of the jog wheel may be relatively big. Having a jog wheel that is large in size limits the potential use of jog wheels in some applications, especially in small handheld computer devices or other small devices. Also, the resolution of conventional jog wheels may be limited to the resolution of the capacitive traces or the number of hall effect sensors implemented in the jog wheel. In the case of capacitive jog wheels, the resolution is typically limited by the size of the conductive object, e.g., fingertip, used as the input device. In the case of hall effect jog wheels, increasing resolution by implementing several hall effect sensors is generally cost-prohibitive.
In view of this, what is needed is a jog wheel to overcome the physical size and resolution limitations of conventional jog wheels.